The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Shilian Wang - One of the best experts on this subject based on the ideXlab platform.
-
Subblocks set design aided orthogonal frequency division multiplexing with all index modulation
IEEE Access, 2019Co-Authors: Yuxin Shi, Kai Gao, Jiang Zhu, Shilian WangAbstract:In recent years, OFDM with index modulation (OFDM-IM) has become a potential technique due to its improvement of diversity gain. In typical OFDM-IM schemes, incoming information bits are divided into two parts, symbols bits, and index bits. However, the symbol bits conveyed by each OFDM symbol suffer from low diversity order, which has a negative impact on diversity gain. In this paper, we propose the scheme called OFDM with all index modulation (OFDM-AIM), which replaces the PSK/QAM constellation modulator with subblock modulator and simplifies the structure. With such an arrangement, the Subblocks of OFDM-AIM become flexible, which contributes to achieving the higher diversity order of the system. Moreover, we study the effects of Euclidean distance and diversity order based on the unconditional pair error probability, which gives the guideline to design a legitimate Subblocks set. Then the algorithm to build the Subblocks set with higher diversity order is proposed, which can achieve better diversity gain. Theoretical and simulated results show that the OFDM-AIM scheme is capable of achieving better BER performance than other index modulated OFDM schemes.
-
orthogonal frequency division multiplexing with joint Subblocks index modulation
IEEE Access, 2019Co-Authors: Yuxin Shi, Kai Gao, Jiang Zhu, Shilian WangAbstract:Recently, orthogonal frequency division multiplexing (OFDM) with index modulation has emerged as promising technologies with the improvement of spectral efficiency and energy efficiency, which carries additional index bits through the index domain. In OFDM-IM, some indices of subcarrier activation patterns are discarded to retain a part of indices to convey index bits, which causes the loss of spectral efficiency. In this paper, we proposed a novel technique to combine indices of a part of Subblocks, called OFDM with joint Subblocks index modulation (OFDM-JS-IM), which is capable of enhancing the spectral efficiency and energy efficiency without extra energy consumption compared to OFDM-IM. The length of joint Subblocks is also discussed to properly enhance spectral efficiency. Moreover, near the maximum-likelihood detector and low-complexity log-likelihood ratio detector are proposed to mitigate the high burden caused by joint Subblocks. Theoretical analysis based on pairwise error probability is conducted which fits well with the simulation results. The Monte Carlo simulations show that the proposed scheme achieves improvement of spectral efficiency with slight performance loss in comparison with OFDM-IM.
Yuxin Shi - One of the best experts on this subject based on the ideXlab platform.
-
Subblocks set design aided orthogonal frequency division multiplexing with all index modulation
IEEE Access, 2019Co-Authors: Yuxin Shi, Kai Gao, Jiang Zhu, Shilian WangAbstract:In recent years, OFDM with index modulation (OFDM-IM) has become a potential technique due to its improvement of diversity gain. In typical OFDM-IM schemes, incoming information bits are divided into two parts, symbols bits, and index bits. However, the symbol bits conveyed by each OFDM symbol suffer from low diversity order, which has a negative impact on diversity gain. In this paper, we propose the scheme called OFDM with all index modulation (OFDM-AIM), which replaces the PSK/QAM constellation modulator with subblock modulator and simplifies the structure. With such an arrangement, the Subblocks of OFDM-AIM become flexible, which contributes to achieving the higher diversity order of the system. Moreover, we study the effects of Euclidean distance and diversity order based on the unconditional pair error probability, which gives the guideline to design a legitimate Subblocks set. Then the algorithm to build the Subblocks set with higher diversity order is proposed, which can achieve better diversity gain. Theoretical and simulated results show that the OFDM-AIM scheme is capable of achieving better BER performance than other index modulated OFDM schemes.
-
orthogonal frequency division multiplexing with joint Subblocks index modulation
IEEE Access, 2019Co-Authors: Yuxin Shi, Kai Gao, Jiang Zhu, Shilian WangAbstract:Recently, orthogonal frequency division multiplexing (OFDM) with index modulation has emerged as promising technologies with the improvement of spectral efficiency and energy efficiency, which carries additional index bits through the index domain. In OFDM-IM, some indices of subcarrier activation patterns are discarded to retain a part of indices to convey index bits, which causes the loss of spectral efficiency. In this paper, we proposed a novel technique to combine indices of a part of Subblocks, called OFDM with joint Subblocks index modulation (OFDM-JS-IM), which is capable of enhancing the spectral efficiency and energy efficiency without extra energy consumption compared to OFDM-IM. The length of joint Subblocks is also discussed to properly enhance spectral efficiency. Moreover, near the maximum-likelihood detector and low-complexity log-likelihood ratio detector are proposed to mitigate the high burden caused by joint Subblocks. Theoretical analysis based on pairwise error probability is conducted which fits well with the simulation results. The Monte Carlo simulations show that the proposed scheme achieves improvement of spectral efficiency with slight performance loss in comparison with OFDM-IM.
Amir Said - One of the best experts on this subject based on the ideXlab platform.
-
image wavelet coding systems part ii of set partition coding and image wavelet coding systems
Foundations and Trends in Signal Processing, 2008Co-Authors: William A Pearlman, Amir SaidAbstract:This monograph describes current-day wavelet transform image coding systems. As in the first part, steps of the algorithms are explained thoroughly and set apart. An image coding system consists of several stages: transformation, quantization, set partition or adaptive entropy coding or both, decoding including rate control, inverse transformation, de-quantization, and optional processing (see Figure 1.6). Wavelet transform systems can provide many desirable properties besides high efficiency, such as scalability in quality, scalability in resolution, and region-of-interest access to the coded bitstream. These properties are built into the JPEG2000 standard, so its coding will be fully described. Since JPEG2000 codes Subblocks of subbands, other methods, such as SBHP (Subband Block Hierarchical Partitioning) [3] and EZBC (Embedded Zero Block Coder) [8], that code subbands or its Subblocks independently are also described. The emphasis in this part is the use of the basic algorithms presented in the previous part in ways that achieve these desirable bitstream properties. In this vein, we describe a modification of the tree-based coding in SPIHT (Set Partitioning In Hierarchical Trees) [15], whose output bitstream can be decoded partially corresponding to a designated region of interest and is simultaneously quality and resolution scalable. This monograph is extracted and adapted from the forthcoming textbook entitled Digital Signal Compression: Principles and Practice by William A. Pearlman and Amir Said, Cambridge University Press, 2009.
Tao Jiang - One of the best experts on this subject based on the ideXlab platform.
-
papr reduction of oqam ofdm signals using segmental pts scheme with low complexity
IEEE Transactions on Broadcasting, 2014Co-Authors: Tao JiangAbstract:In this paper, a novel segmental partial transmit sequence (S-PTS) scheme is proposed for the peak-to-average power ratio (PAPR) reduction in offset quadrature amplitude modulation based orthogonal frequency-division multiplexing (OQAM-OFDM) systems. The key idea of the S-PTS scheme is to divide the overlapped OQAM-OFDM signals into a number of segments, and then some disjoint Subblocks are divided and multiplied with different phase rotation factors in each segment. Compared with the conventional PTS scheme directly employed in OQAM-OFDM sytems, the S-PTS scheme could offer better PAPR reduction with lower computational complexity.
-
multi block joint optimization for the peak to average power ratio reduction of fbmc oqam signals
IEEE Transactions on Signal Processing, 2013Co-Authors: Tao JiangAbstract:Recently, the filter bank multicarrier with offset quadrature amplitude modulation (FBMC-OQAM) has attracted increasing attention. However, most peak-to-average power ratio (PAPR) reduction schemes developed for orthogonal frequency division multiplexing (OFDM) signals are not effective for FBMC-OQAM signals, due to the overlapping structure of FBMC-OQAM signals. In this paper, we propose an improved partial transmit sequence (PTS) scheme by employing multi-block joint optimization (MBJO) for the PAPR reduction of FBMC-OQAM signals, called as MBJO-PTS scheme. In PTS scheme, one data block is divided into several Subblocks and each subblock is multiplied by a phase rotation factor for the subblock. The PTS scheme searches over all combinations of allowed phase factors to lower the PAPR. Unlike existing PAPR reduction schemes of independently optimizing the data blocks, the MBJO-based scheme exploits the overlapping structure of the FBMC-OQAM signal and jointly optimizes multiple data blocks. Moreover, we develop two algorithms for the optimization problem in the MBJO-PTS scheme, including a dynamic programming (DP) algorithm to guarantee the optimal solution and avoid exhaustive search. Theoretical analysis and simulations show that the proposed MBJO-PTS scheme could provide a significant PAPR reduction in the FBMC-OQAM system, by exploiting the overlapping structure of the FBMC-OQAM signal. Employing the proposed DP algorithm, the FBMC-OQAM system with the proposed MBJO-PTS scheme even outperforms the OFDM system with the conventional PTS scheme by 0.9 dB at CCDF of 10-3 in PAPR reduction, under the same number of subcarriers, modulation type and PTS parameters given in Section V.
Kai Gao - One of the best experts on this subject based on the ideXlab platform.
-
Subblocks set design aided orthogonal frequency division multiplexing with all index modulation
IEEE Access, 2019Co-Authors: Yuxin Shi, Kai Gao, Jiang Zhu, Shilian WangAbstract:In recent years, OFDM with index modulation (OFDM-IM) has become a potential technique due to its improvement of diversity gain. In typical OFDM-IM schemes, incoming information bits are divided into two parts, symbols bits, and index bits. However, the symbol bits conveyed by each OFDM symbol suffer from low diversity order, which has a negative impact on diversity gain. In this paper, we propose the scheme called OFDM with all index modulation (OFDM-AIM), which replaces the PSK/QAM constellation modulator with subblock modulator and simplifies the structure. With such an arrangement, the Subblocks of OFDM-AIM become flexible, which contributes to achieving the higher diversity order of the system. Moreover, we study the effects of Euclidean distance and diversity order based on the unconditional pair error probability, which gives the guideline to design a legitimate Subblocks set. Then the algorithm to build the Subblocks set with higher diversity order is proposed, which can achieve better diversity gain. Theoretical and simulated results show that the OFDM-AIM scheme is capable of achieving better BER performance than other index modulated OFDM schemes.
-
orthogonal frequency division multiplexing with joint Subblocks index modulation
IEEE Access, 2019Co-Authors: Yuxin Shi, Kai Gao, Jiang Zhu, Shilian WangAbstract:Recently, orthogonal frequency division multiplexing (OFDM) with index modulation has emerged as promising technologies with the improvement of spectral efficiency and energy efficiency, which carries additional index bits through the index domain. In OFDM-IM, some indices of subcarrier activation patterns are discarded to retain a part of indices to convey index bits, which causes the loss of spectral efficiency. In this paper, we proposed a novel technique to combine indices of a part of Subblocks, called OFDM with joint Subblocks index modulation (OFDM-JS-IM), which is capable of enhancing the spectral efficiency and energy efficiency without extra energy consumption compared to OFDM-IM. The length of joint Subblocks is also discussed to properly enhance spectral efficiency. Moreover, near the maximum-likelihood detector and low-complexity log-likelihood ratio detector are proposed to mitigate the high burden caused by joint Subblocks. Theoretical analysis based on pairwise error probability is conducted which fits well with the simulation results. The Monte Carlo simulations show that the proposed scheme achieves improvement of spectral efficiency with slight performance loss in comparison with OFDM-IM.
